In the 2014 update to After Effects CC, which is available today, the technology used for video preview on an external monitor has been replaced with Mercury Transmit technology from Premiere Pro. Read about it in detail here:

So as far as I understood, now we are able to preview ror example simple HD video footage (without ffx) realtime like in Premiere Pro?

No prerender is required?

Alex, your question implies that you think that these changes will affect how After Effects plays back footage. That is incorrect. These changes only affect how video frames are delivered to external video preview monitors. RAM preview is still required to get real-time preview.

This is a good opportunity to address a misconception about After Effects that I've seen lately. Some people say that After Effects can not play back in real-time, which is incorrect. After Effects can play back in real-time once RAM preview is built.

It'd be great to have some sort of native LUT support as an alternative to the ICC profiles in AE too. It's been a while since Adobe have done a white paper on Digital Cinema image processing, perhaps it's time?

We have not had success getting acceptable RAM Preivews to broadcast monitors via Kona 3 cards in any AE CC 2014 release. (Just updated to the 13.1.0.111 release today to test). We do get acceptable RAM Previews to broadcast monitors via Kona 3 cards using AE CC on the very same computer. These are Mac Pro's with 16 to 32 GB of ram and 2 x 2.4 Quad-Core Xeons, Nvidia Quadro FX4800 and better video cards.

We have the latest versions of AJA driver and AJA Adobe plugin installed.

Our problem (with a 1920x1080 29.97 Composition for example) is that the output of of the AJA card is either way out of sync with the computer sceen or seemingly running at almost half speed. Again this does not happen with AE CC, just AE CC 2014.

I will also mention that there is not a clear setup procedure that I can find on how to configure a system like this. Is there one? The notes pertaining to Mercury Transmit and AE and AJA mentioned earlier here seem to suggest that I should uninstall the AJA Adobe plugin. But the Adobe support page says that we should be using that plugin with AE CC 2014.

It's your choice if you wish to use Mercury Transmit with your AJA cards, or the AJA Preview plug-in. You do not need to uninstall anything, but you should disable the one you are not using.

The differences between the two are subtle, but can be simplified (very grossly simplified) to speed vs. accuracy.

The AJA Preview plug-in has a performance advantage over Mercury Transmit. AJA is able to optimize the frame throughput because they have better access to their hardware. You should be able to get real-time previews under most circumstances.

Mercury Transmit has better access to the After Effects pixel buffer than the AJA Preview plug-in. For example, when color management is enabled in the project, Mercury Transmit will apply color transforms. These color transforms require additional processing, which can slow down the preview speed and drop it below real-time.

Performance of video preview in After Effects (any version, using any of the available technologies) otherwise tends to be a straightforward equation of the computer's processor horsepower vs. the requirements of the frames being pushed (frame size + frame rate + color depth + color management). In the "performance of RAM preview when video preview is enabled" section of this page, I've detailed what levers you can pull to affect the performance of video preview in After Effects:

If you continue to have problems, please post more detail about the settings you are using, especially whether you are using greater than 8-bpc color or color management in the project. Machine specs and the state of the machine, including the amount of RAM, free RAM, and other applications running, will also be helpful. Please also state, given all of the above, what frame rate is being reported in the Info panel during RAM preview playback.

Thanks for the feed back. Really basic question on my part - how EXACTLY do I choose to "use Mercury Transmit with your AJA cards, or the AJA Preview plug-in". Can you give me step by step? I feel that I am missing something basic, as it is not obvious to me how to manage this choice.

I think I figured it out. My confusion (for your UI design folks) was that there is no real indication that the switch in the Preferences > Video Preview is different from Window > AJA Preview. Documentation on this is lacking in the Adobe world as well as the AJA world.

Apologies for the confusion between the two, AJA is unique in that they offer a plug-in that offers an alternative video preview option. As a plug-in, they are taking advantage of an API that is very similar to how Mercury Transmit works, but that particular API doesn't automatically provide a user interface. So they built their own out of necessity, thus it is a separate window. I hope that makes sense.

I am unable to use Mercury Transmit for previews with my AJA LHi since the 13.1 update. When I create a new comp it will display a frame but then will not update as I step through the timeline, ram previews are just a frozen frame. If I jump to a different comp then it displays the current frame but to change to a different frame I have to move to the specific frame and then swap to another comp and then come back.

I am able to use the AJA preview but would rather use Mercury Transmit as it displays previews made at half resolution as full screen on my Broadcast Monitor which the AJA Preview won't do, it displays a half size image.

I am running on a MacPro 5,1 with OS x 10.9.5 working mainly at 1080 25

Thanks, Nic. I am able to reproduce this problem with the 10.5.2 drivers and an AJA Io XT. The problem happens for me with both After Effects CC 2014 (13.0) and After Effects CC 2014.1 (13.1), so I don't think the problem is specific to the update. Other Mercury Transmit devices are working for me.

This is strange, because I specifically remember testing the 10.5.2 drivers after their release, and not having any problems. I have contacted AJA about this problem.

I think the problem goes beyond the IO XT. Now that I understand the methodology of choosing either the Mercury Transmit or AJA Adobe Plugin, I can report that I get no RAM preview out of our Kona 3 when Mecury Transmit only is selected.

I had a conversation with AJA about this issue. They currently recommend that you use the AJA Preview plug-in, not Mercury Transmit, for video preview from After Effects with AJA hardware due to its better performance capabilities.

AJA is the only Mercury Transmit device that is exhibiting this problem, so we will continue to work with them. Until then you should follow their recommendation and use only the AJA Preview plug-in.